When a group of motorcyclists try to shut down a bridge that provides access to a major American city, it's going to lead to a showdown with law enforcement. And these bikers admit they're doing it just for fun. But for law enforcement, the danger is real. ABC's juju Chang was there on the inside with cameras rolling as it happened. The rumor is that it will be over 100 motorcycle operators. Saturday, just start seeing all of them rolling. We know people in the motorcycle community. There is a small minority that give them a bad name. The cops say you're breaking the law. Well, We're on one wheel, we're running the stoplights, stop signs. The cops, it's their job to prevent you from doing it. My first collision was my mother and my brother in a head-on collision with a drunk driver. I take safety very seriously. We know something is going to happen on Saturday. It's inevitable, man. Until you ride with a group of 400 or 500 bikes, 1,000 bikes or whatever and you ride through a town, there's nobody out there in their right mind that's going to try to challenge you. Every city has its landmark. In Charleston, South Carolina, it's the ravanel bridge. Chad plans to lead hundreds of bikers to block it, stop traffic, and take it over as a private playground for private stubt biking. They call it the chuck town shutdown. Casting a shadow over the plans -- this video which made national news. A stunt ride on a New York City highway. A group of bikers blocked traffic. An SUV pinned in the group makes contact with the biker. The group reacts, surrounding the vehicle. The panicked motorist drivers over a biker and seriously injuries him. The bikers take off in pursuit. And after this video ends, pulled from his car and beaten in front of his wife and daughter. Now everybody across the nation thinks when there's a pack of bikes it's a bunch of goons looking to beat up freaking women and rape children and It's nothing like that. So a few weeks after the incident, Chad and his bikers invite us to spend time with them as they plan and attempt the shutdown. What's the thrill of doing that out on the open road? You're not supposed to do it. Are you a menace to society? No. Can I at sometimes be a pain in the authority's as? Yes. The highway is not a place T do a stunt. Law enforcement plans to show up in force and stop the shutdown. Do you anticipate conflict? No, ma'am. They've got to understand what our job is. And it's law enforcement. And all it takes is one little tiny thing and we've got a ten-car pile-up. Reporter: Captain woods has been riding motorcycle seasons he was 12 years old. He spent his entire career in law enforcement. This is a unique situation. Reporter: You're prepared for the worst? We are. What we're guarding against is them blocking those intersections so they can go through without stopping. On the mornings of the shutdown, some of the bikers are worry about getting arrested. I don't want to call out of work on Monday. I got money just in case I need to get bailed out. Jimmy: The turnout is smaller than last year, but the die-hards show up. This piece of machine right here. Everything that I live for, erg that I die for. This is my life. I have PTSD. My bike is what teep kooep keeps me levelheaded. Anybody makes any contact, get on the radio and let us know you've got a group so we can get other people there quicker. Chad switches the start location for the shutdown. No, no, that's not where we're going. Some things we're hearing is that the overall thing is D canced. Some say there's 180 riders. You just don't know. Reporter: You set up decoys online. You got to. Be safe, be careful. Spread out on the interstate, please. I feel good. It's a beautiful day. Out riding motorcycles. Can't beat that. Cops have arrived. Helicopter. Their helicopter is slow. We're a lot faster. Got about 15 cops waiting on us. We have cops that way waiting on us. But we're just going to switch up the route. Reporter: Chad seems to be making it up as we go along. We don't know where with we're going? This is seriously a concentration. If they block traffic, you all take care of that. The police can't arrest them for simply wanting to shut down the bridge. They start pulling over bikers for any traffic violations. What happened? And as the police begin to infiltrate, the ride breaks up into smaller groups. The brook led by Chad are the first to reach the highway. The cops think they're ahead of the game. They think they know where we're going and what we're doing. We're just rerouting ourself right now, that's all. Now catching up to the front group. Nothing is more nerve wracking than seeing 50 motorcycles in your rear-view mirror. Half an hour into the ride, the bikers have regrouped and can see the bridge. They've moved to the onramp for the Ravenel bridge. Spread out a little bit. All the lanes are blocked. As the bikers begin amassing on the bridge, law enforcement moves to the front. Suddenly police converge on the lead biker with an exposed weapon. They're surrounding me. All drew their guns on me. Keep your Hands on the bike! You . It's nerve wracking. You've got a lot of motorcycles. A lot of thing goings on. How's your blood pressure? Good, I'm legal. That's why I stopped. If I wasn't legal, I wouldn't have stopped. But the pullover stops the momentum. It effectively puts an end to the shutdown. The police escort the bikers to their stunt lot. We didn't accomplish what we really wanted to. We really wanted to have some fun on the street. But they came with a really strong opposing force. My goal was for no one to get injured. Nobody hurt, no crashes. We got all those motorcycles over here without that happening. So I'm very pleased about that. It's not like we robbed a bank, murdered anybody. We did a wheelie, we ran a stoplight, we sped. Big deal. We're not discouraged at all. We'll keep going. I think we had more fun trying to lose the cops than anything else. Reporter: What if they weren't there? Would the ride have gone different? Would you have done different things? Owe, yeah. Reporter: I'm juju Chang for "Nightline," Charleston, south Carolina. Fascinate access to both sides of that story. Thanks, juju. Next, facing a flood of

This transcript has been automatically generated and may not be 100% accurate.